本文实例为大家分享了C语言实现发送邮件的具体代码，供大家参考，具体内容如下
首先需要知道发送邮件的服务器IP地址和端口，我这里使用的是网易的126邮箱，如果是其他邮箱需要替换成其他的邮箱域名，域名和端口一般可以在邮箱网页的帮助项里面找到。用域名比较方便维护以免后续更换ip之后还要修改代码。
发送邮件一共需要8个步骤，具体见代码main函数里面的注释
代码中的用户名密码以及收件人发件人等信息需要修改为你自己的。而且用户名和密码需要进行base64编码后才能发送，具体base64算法没有贴了，百度上到处都是。
完整代码如下：
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#include <stdio.h>#include <stdlib.h>#include "winsock2.h"extern int Base64Encod(char * data,char *output,int len,int *oputlen);#define EMAIL_SERVER "smtp.126.com" //按需修改int CreateSocketAndConnect(){ struct sockaddr_in server_addr; struct hostent *Addr; int ret; int sock = socket(AF_INET, SOCK_STREAM, 0); if(sock < 0){ printf("sock create failed\n"); return -1; } Addr = gethostbyname(EMAIL_SERVER); //用域名获取对应IP if(Addr == NULL){ printf("get ip error\n"); return -1; } server_addr.sin_family = AF_INET; server_addr.sin_port = htons(25); server_addr.sin_addr.S_un.S_addr = (*(struct in_addr*)Addr->h_addr_list[0]).S_un.S_addr; ret = connect(sock, (struct sockaddr *)&server_addr, sizeof(server_addr)); if(ret < 0){ printf("connect server failed\n"); return -1; } return sock;}int server_send_recv_display(int sock, char *buff){ int ret = 0; char recvbuff[320] = {0}; send(sock, buff, strlen(buff), 0); ret = recv(sock, recvbuff, 320, 0); printf("服务器返回消息:len = %d \n recv:[%s] \n",ret,recvbuff); return ret;}/*HELO*/int email_send_helo_fun(int sock){ char buff[320] = {0}; int ret; sprintf(buff, "HELO 126.com\r\n"); ret = server_send_recv_display(sock, buff); if(ret <= 0) { return -1; } return 0;}/*AUTH LOGIN 身份认证*/int email_send_authlogin_fun(int sock){ char buff[320] = {0}; int ret; sprintf(buff,"%s","AUTH LOGIN\r\n"); ret = server_send_recv_display(sock, buff); if(ret <= 0) { return -1; } return 0;}//发送用户名int email_send_username_fun(int sock){ char buff[320] = {0}; char encbuff[120] = {0}; int ret, len = 0; sprintf(buff, "xxxxxxxxxx@126.com"); //需要改成自己的用户名 Base64Encod(buff, encbuff, strlen(buff), &len); memset(buff, 0x00, sizeof(buff)); sprintf(buff,"%s\r\n",encbuff); ret = server_send_recv_display(sock, buff); if(ret <= 0) { return -1; } return 0;}//发送密码int email_send_password_fun(int sock){ char buff[320] = {0}; char encbuff[120] = {0}; int ret, len = 0; sprintf(buff, "123456789"); //需要改成自己的密码，有的邮箱是需要填授权码不是登录用的密码 Base64Encod(buff, encbuff, strlen(buff), &len); memset(buff, 0x00, sizeof(buff)); sprintf(buff, "%s\r\n", encbuff); ret = server_send_recv_display(sock, buff); if(ret < 0){ return -1; } return 0;}//发送发件人int email_send_from_fun(int sock){ char buff[320] = {0}; int ret; sprintf(buff, "MAIL FROM: <xxxxxxxxxx@126.com>\r\n"); ret = server_send_recv_display(sock, buff); if(ret < 0){ return -1; } return 0;}//发送收件人int email_send_to_fun(int sock){ char buff[320] = {0}; int ret; sprintf(buff, "RCPT TO: <xxxxxx@163.com>\r\n"); ret = server_send_recv_display(sock, buff); if(ret < 0){ return -1; } return 0;}//通知服务器准备发送邮件int email_send_ready_fun(int sock){ char buff[320] = {0}; int ret; sprintf(buff, "DATA\r\n"); ret = server_send_recv_display(sock, buff); if(ret < 0){ return -1; } return 0;}//发送邮件int email_send_maintext_fun(int sock){ char buff[320] = {0}; int ret; sprintf(buff, "From: \"pc\"<xxxxxxxxxx@126.com>\r\n" //发件人 "To: \"con\"<xxxxxx@163.com>\r\n" //收件人 "Subject: email test\r\n\r\n" //主题 "test:\r\n" //正文, 以 \r\n.\r\n 结束 " line1\r\n" " line2\r\n.\r\n"); ret = server_send_recv_display(sock, buff); if(ret < 0){ return -1; } return 0;}#define MAX_BUFF_SIZE 512int main(){ int sock; char buff[MAX_BUFF_SIZE]; WSADATA wsa; int ret; if(WSAStartup(MAKEWORD(1,1), &wsa) != 0){ printf("WSA startup failed\n"); return 1; } sock = CreateSocketAndConnect(); if(sock < 0){ return -1; } printf("connect to server success\n"); memset(buff, 0x00, sizeof(buff)); while(1){ ret = recv(sock, buff, MAX_BUFF_SIZE, 0); if(ret < 0){ printf("recv error\n"); continue; } printf("%s", buff); break; } //1.send helo if(email_send_helo_fun(sock) < 0){ return 1; } //2.send auth login if(email_send_authlogin_fun(sock) < 0){ return 1; } //3.send username if(email_send_username_fun(sock) < 0){ return 1; } //4.send password if(email_send_password_fun(sock) < 0){ return 1; } //5.send from if(email_send_from_fun(sock) < 0){ return 1; } //6.send to if(email_send_to_fun(sock) < 0){ return 1; } //7.send notice ready if(email_send_ready_fun(sock) < 0){ return 1; } //8.send email if(email_send_maintext_fun(sock) < 0){ return 1; } closesocket(sock); return 0;} |
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：https://blog.csdn.net/LIZHI1994/article/details/119328035
